# Problem: Using the van't Hoff factors in the table below, calculate the mass of solute required to make each aqueous solution.Van't Hoff factors at 0.05 m concentration in aqueous solutionSoluteExpectedMeasuredNonelectrolyte11NaCl21.9MgSO421.3MgCl232.7K2SO432.6FeCl343.4Calculate the mass of solute required to make a sodium chloride solution containing 161 g of water that has a melting point of -1.9 oC.

###### FREE Expert Solution

Recall that the freezing point of a solution is lower than that of the pure solvent and the change in freezing point (ΔT­f) is given by:

The change in freezing point is also related to the molality of the solution:

$\overline{){{\mathbf{\Delta T}}}_{{\mathbf{f}}}{\mathbf{=}}{{\mathbf{imK}}}_{{\mathbf{f}}}}$

where:

i = van’t Hoff factor

m = molality of the solution (in m or mol/kg)

Kf = freezing point depression constant (in ˚C/m)

Recall that the molality of a solution is given by:

92% (361 ratings)
###### Problem Details
Using the van't Hoff factors in the table below, calculate the mass of solute required to make each aqueous solution.
Van't Hoff factors at 0.05 m concentration in aqueous solution
 Solute Expected Measured Nonelectrolyte 1 1 NaCl 2 1.9 MgSO4 2 1.3 MgCl2 3 2.7 K2SO4 3 2.6 FeCl3 4 3.4

Calculate the mass of solute required to make a sodium chloride solution containing 161 g of water that has a melting point of -1.9 oC.